user@threatcheck.sh ~ threat-analysis
bash
$ analyze-threat Backdoor:Linux/Gafgyt.BF!MTB
Backdoor:Linux/Gafgyt.BF!MTB - Windows Defender threat signature analysis

Backdoor:Linux/Gafgyt.BF!MTB - Windows Defender Threat Analysis

$ cat analysis.txt
=== THREAT ANALYSIS REPORT ===
Threat Name: Backdoor:Linux/Gafgyt.BF!MTB
Classification:
Type:Backdoor
Platform:Linux
Family:Gafgyt
Detection Type:Concrete
Known malware family with identified signatures
Variant:BF
Specific signature variant within the malware family
Suffix:!MTB
Detected via machine learning and behavioral analysis
Detection Method:Behavioral
Confidence:Very High
False-Positive Risk:Low

Concrete signature match: Backdoor - Provides unauthorized remote access for Linux platform, family Gafgyt

Summary:

This detection identifies a Linux backdoor from the Gafgyt malware family, a botnet primarily used for launching Distributed Denial-of-Service (DDoS) attacks. Although detected on a Windows system, the threat targets Linux environments, such as servers, IoT devices, or the Windows Subsystem for Linux (WSL). Once executed on a compatible system, it connects to a command-and-control server to await instructions.

Severity:
Medium
VDM Static Detection:
No specific strings found for this threat
YARA Rule:
rule Backdoor_Linux_Gafgyt_BF_2147816317_0
{
    meta:
        author = "threatcheck.sh"
        detection_name = "Backdoor:Linux/Gafgyt.BF!MTB"
        threat_id = "2147816317"
        type = "Backdoor"
        platform = "Linux: Linux platform"
        family = "Gafgyt"
        severity = "Critical"
        info = "MTB: Microsoft Threat Behavior"
        signature_type = "SIGNATURE_TYPE_ELFHSTR_EXT"
        threshold = "10"
        strings_accuracy = "Low"
    strings:
        $x_4_1 = {49 b9 01 01 01 01 01 01 01 01 40 0f b6 d6 4c 0f af ca 49 b8 ff fe fe fe fe fe fe fe 66 66 66 90 66 66 90 66 66 90}  //weight: 4, accuracy: High
        $x_4_2 = {48 8b 08 48 83 c0 08 4c 89 c2 4c 31 c9 48 01 ca 0f 83 [0-8] 48 31 ca 4c 09 c2 48 ff c2 0f 85 [0-8] 4c 31 c9 4c 89 c2 48 01 ca 0f 83 [0-8] 48 31 ca 4c 09 c2 48 ff c2 0f 85 [0-8] 48 8b 08 48 83 c0 08 4c 89 c2 4c 31 c9 48 01 ca 0f 83 [0-8] 48 31 ca 4c 09 c2 48 ff c2 0f 85 [0-8] 4c 31 c9 4c 89 c2 48 01 ca 73 75 48 31 ca 4c 09 c2 48 ff c2}  //weight: 4, accuracy: Low
        $x_1_3 = "TSource Engine Query" ascii //weight: 1
        $x_1_4 = "npxXoudifFeEgGaACScs" ascii //weight: 1
        $x_1_5 = "bot.com/crawler" ascii //weight: 1
        $x_1_6 = "nf1dk5a8eisr9i32" ascii //weight: 1
    condition:
        (filesize < 20MB) and
        (
            ((2 of ($x_4_*) and 2 of ($x_1_*))) or
            (all of ($x*))
        )
}
Known malware which is associated with this threat:
Filename: sync.x86_64
2df09bfb9a61837bdc68cd2c895e4802deb2148198d76e4b5988bc90c01980c4
04/12/2025
→VirusTotal↓Download Sample
Filename: SecuriteInfo.com.Linux.Siggen.1179.31526.7276
b123c0917c68522fc7c5e8cf64555276595b22418aaaa91eb08a21b736bea5ea
20/11/2025
→VirusTotal↓Download Sample
Remediation Steps:
1. Use your security software to quarantine and remove the detected file. 2. Investigate the file's origin to determine how it arrived on the system (e.g., download, WSL). 3. Scan your network for other vulnerable Linux or IoT devices and immediately change any default credentials to strong, unique passwords.
=== END REPORT ===
$ reanalyze-threat
This analysis was last updated on 20/11/2025. Do you want to analyze it again?
$ ls available-commands/
→ cd /home
user@threatcheck.sh:~$ ▊